1. Field of the Invention
The present invention relates to a method of detecting any negative film frame which need not be printed which is employed when color printing is effected by the use of an exposed negative color film.
2. Description of the Prior Art
When the images on an exposed negative color film are printed on photographic paper, there may be negative film frames which are not worthy of being printed. Such negative film frames may be roughly classified as follows: The first type of improperly exposed negative film frame includes "ultra-underexposed" negative film frames which have an extremely low photographic density due to underexposure and "ultra-overexposed" negative film frames which conversely have an extremely high photographic density due to overexposure. The second type of improperly exposed negative film frames includes negative film frames carrying images which are out of focus and negative film frames which were mistakenly not exposed at all. As to these two types of improperly exposed negative film frames, means have already been proposed (for example, Japanese Patent Laid-Open Nos. 3,224/1976 and 192,941/1982) by which these improperly exposed negative film frames are positively detected before printing so that they are prevented from being printed.
The third type of improperly exposed negative film frames includes negative film frames which were exposed intentionally or by an operational mistake at the leading end portion or an intermediate portion of a film. In order to detect the third type of improperly exposed negative film frames, a means has been proposed by which a notch, which is normally formed as a confirmation mark by which a negative film frame is recognized as one to be printed, is not formed in a negative film frame which has been exposed at a film edge portion thereof which is outward of a perforation formed at each of the widthwise edges of a negative film. Such confirmation notches or marks are, however, often applied on all the developed negative film frames in a step previous to printing and, therefore, the above-described means is not always reliable in detecting a negative film frame which need not be printed.